The invention relates to a microwave switch which can be set into at least two different switching positions for the selective connection of at least one coaxial input line with at least one of two output lines of which at least one is a coaxial line. The switch serves to switch HF signals.
DE-OS No. 3,122,780 discloses a coaxial T switch which has three transmission positions between pairs of four plug-in connectors, with the switching elements being provided in the form of planar line segments which either lie against the walls of cavities or are arranged in the center of cavities. If a line segment lies against the wall of a cavity, it is short-circuited toward the cavity and is separated from the inner conductors of the coaxial connector. If the line segment is disposed in the center of the cavity, the ends of the line segment are also in contact with the inner conductors of the coaxial connector since the inner conductors of the coaxial connector are disposed in juxtaposition to the ends of the line segment.
A cavity is disposed in a certain plane and is configured in the form of a plurality of cavity sections. In particular, the cavity has an outer, circumferential portion which is subdivided into three outer cavity sections. Three radial cavity sections begin at a central point of the circumferential portion and intersect the ends of the three outer cavity sections. A first coaxial connector is disposed at the central location, while three additional coaxial connectors are disposed at the points of intersection between the radial cavity sections and the outer cavity sections. A single line segment is disposed in each cavity section and is movable between a position at the wall of the cavity and remote from the inner conductors and a central position in the cavity section where it is in contact with the inner conductors. The total of six line segments correspond in number and shape to the cavity sections so that three line segments extend radially outwardly beginning at a central location while three line segments are arranged around the three radial line segments in such a manner that they form a circumferential segment.
The various line segments can be actuated individually so that signals can be transmitted between pairs of coaxial connectors.
It has been found that the prior art coaxial switches, due to their existing mechanical contacts, are less reliable and have relatively poor high frequency characteristics. Moreover, if a plurality of such switches are connected in series, e.g. if they are employed in redundant amplifier circuits as they are used in space travel, the transmission characteristics of the signals conducted through a plurality of such switches become very poor.